Process of pigmenting surfaces and apparatus therefor



Dec. 15, 1936. l Q A `WULF 2,064,284

PROCESS OF PIGMENTING SURFACES AND APPARATUS THEREFOR Filed Feb. l, 1934 2 Shee'ts-Sheet 1 A F l 1l 5 f 3 L \r /V INVENTOR.

BY Mf ATTORNEYS Dea 15, 1936. C, A, WULF 2,064,284

PROCESS oF PIGMENTING IsURFAoEs AND APPARATUS THEREFOR Filed Feb. 1, 1934 '2 sheets-Sheet 2 Patented Dec. 15, 1936 UNITED STATES PATENT OFFICE PROCESS F PIGMENTING BUBFACES AND APPARATUS THEBEFOR Application February 1, 1934, Serial No. 709,312

'i claims. (Crm1-12s) My present application relates to a method of pigmenting surfaces and apparatus therefor, and more particularly to a method of, and apparatus for, producing multi-color designs upon porcelain enamel, and similar surfaces.

While the method and apparatus have been produced primarily for the application of multicolored pigments to enameled sheet metal surfaces in such manner and form that the resultant multi-color design may be rendered permanent by a single firing operation, it will be readily understood that the invention is by no means limited thereto.

The accompanying drawings illustrate my invention.

Fig. 1 is a plan of an apparatus embodying my invention; f

Fig. 2 is an end elevation on a smaller scale;

Fig. 3 is a side elevation on the scale of Fig.

Fig. 4 is a fragmentary vertical section on the scale of Fig. l; y

Fig. 5 is a fragmentary vertical section illustrating the reaction of the pigment screen during application of the pigment;

Fig. 6 is a diagram illustrating various stages of the method;

Fig. '7 is a diagrammatic vertical section of the screen fabric at various stages;

Fig. 8 is a fragmentary perspective of one corner of the pigment screen frame and adjacent parts, and

Fig. 9 is a perspective of one of the spring gauge fingers.

In the drawings I0 indicates a table top provided with a multiplicity of perforations II, any one of which is adapted to receive a pole I2 of an electromagnet M. The pole pieces I2 of magnets M are preferably detachably connected by bolts I3 to the ends of a spacer I4 upon which the energizing coil I5 is mounted. Spacers I4 may be provided in various lengths such that poles I2 may be properly spaced to project through any desired pair of table perforations II and each pole, near its outer end, is transversely notched at I6 to receive one end of a lock strip I1 which, projecting into two of such notches and lying upon the upper surface of the table, as illustrated in Fig. 4, serves to retain the magnet in operative position with the upper ends of all of the magnets in a common horizontal plane. f

By this arrangement any desired arrangement of magnet poles may be provided so as to provide suiiicient magnetic force at properly spaced points to insure a holding of the pigment receiving plate P perfectly nat for the reception of the pigments.

Plates P, if of material which has been firetreated to provide an enameled face, are unavoidably warped by the fire treatment, but the above-described magnetic holding table, when the magnets are 'properly placed, insures atness of the plate during the periods of subsequent pigment application.

For convenience in operating upon plates P of widely varying sizes, the table IU may be conveniently formed in two sections A and B (Figs. l and 3) connected by hinge 20, with the section A as the permanent top of the frame F and the section B supportable, in the plane of section A, by a leg L.

Along the rear edge of section A of the table top I0 I provide a guideway 25 upon which are slidably mounted two plates 26, 26 which` may be held in any desired position of relative spacing by the clamping bolts 21, 2l. Each of these plates is provided with a pair of spaced upwardly-extending fingers 28, 29, between which may be received one of a pair'of pins 30 carried by screen frame S. Adjacent the finger 28 there# is secured to each plate 26 an upstanding :post 62, each of which is formed with a plurality of perforations 62 for selectively receiving'stop pins 3| and 32 projectible across the space be# tween the ngers 28 and 29 to limit the vertical movement of the pins 30 in both directions. As shown, said posts 62 are rectangular in cross section, and one corner of each post is pro-vr vided with a plurality of vertically spaced kerfs or notches 63 adjacent its uper end. `A loop 64 at the upper end of each of a. pair of coiled springs 34 is adapted to be selectively'received in any one of said kerfs 63. The lower ends of said springs 34 are, as shown, connected to the pins 30 so that, when said loops 64 are hung in said kerfs 63, the rearward end of the frame S will be resiliently supported above the table surface; the equilibrium elevation of said end above the table surface being variable by selection of the kerfs 63 in which said loops 64 are engaged.

The frame S is conveniently formed of channelled bars in order to be rigid, and4 secured to its under face is a ne mesh screen 35, the mesh of which is sufficiently fine, as is well known in this art, to retain the pigment except when the pigment is forcibly pressed therethrough. This screen may be madelof bolting cloth, or other .Similar material but I have found that the-best `spring anchored at one end.

results are attainable by using a very ilne copplate P so that the screen may be contacted with the plate only by pressure exerted by the squeegee 50, to be described.

In addition to the perforations Il table I is provided, conveniently, with a large number of perforations It' which may be threaded to receive fastening screws for retaining the centering `bracket 33 or for retaining in place gauge fingers 33 or 40.

'I'he gauge fingers 39 and 40 are positioned to accurately position the plate P relative to the pattern produced on the screen 35 and finger 40 is convenientlymade in the form of a leaf Screen frames S of various sizes appropriate to the various articles which are to be manipulated may be provided and the springs 34 are proportioned and adjusted to be capable of sustaining the weight of the rear end of a-'selected frame and super-imposed pigment.

A screen of appropriate size will have .superimposed upon its fabric 35 a desired pattern and those portions of the fabric forming the general background for the pattern, indicated at 50 (Fig.- 6) will be filled with a filler 5I (Fig. 7) so as to be impervious to the pigment which is to be used. This flller i is conveniently a-waterinsoluble glue.

The pattern portion of the screen is then lled with a filler 52, which is impervious to pigment. The filler 52 is of such character as to be soluble inv a reagent in which filler 5I is insoluble, whether or not the nller 52 has been exposed to light. This nller 52 also is of such character that when a portion thereof is exposed to light the exposed or unexposed portion, one or the other, becomes insoluble in a reagent in which the other portion is soluble, and as to which the filler 5I is insoluble.

Those portions of the screen which are permeated by the nller 52 are then exposed to a patterned light and then subjected to the selected reagent which is capable of dissolving eitherthe exposed or unexposed portion, thus rendering the selected portions 53 of the screen permeable to the pigment. The plate P is closely surrounded by strips 5| (Figs. 1 and 4),

1 and the free end of screen S swung down to thel position shown in Fig. 4.' In this position that portion of the screen immediately above plate P lies entirely free from the plate and. because of the elevation of the frame produced by springs 34, inclines slightly upwardly away from the operator. A sufficient quantity of pigment having been placed upon the screen, across its width, at the elevated end of the screen, the operator presses the screen down by means of a squeegee 53 and sweeps the pigment toward him, the squeegee acting t'. depress the screen upon the upper face of plate P and propel the pigment through the open portions 53 of the screen, the pigment coalescing on the under face of the screen immediately in advance of the squeegee.

, As the squeegee is moved toward the operator the screen promptly from the surface of plate P immediately adjacent the squeegee as indicated in Fig. 5, both the lowering of the screen into contact with the upper surface of the plate and the raising of the screen from contact with the surface of the plate being progressive, immediately adiacent the squeegee, as indicated in Fig. 5, as the squeegee is drawn toward the operator. The blocking strips 3|, and the support of screen B, are of such character that except as the screen is forcibly depressed from its normal plane, no portion thereof may contact the upper surface of plate P.

'I'his operation results in depositing upon the upper surface of plate P the pigment in desired pattern as indicated at 55 (Fig. 6). After the screen has served its purpose in the desired permeable pattern the permeable portions arefllled with filler 5I. The remaining portions of ller 52 are then dissolved and the screen again used in the manner described- The several permeable portions of the screen should be accurately formed so that adjacent pigments will have edge contact but will not overlap.

By a proper sequence of illlers and light treatments the screen may be used to apply any desired color patterns of pigments to the plates P, whereupon the screen may be subjected to a solvent which will remove all filler therefrom and again become available for another set of operations.

The fabric 35 may be prepared by any well known, or other, method so as to be pigment-permeable in a desired pattern. However, in order that satisfactory results may be attained, it is pivot on that bracket, or fingers 23 and 29 may.

be slightly curved to approximate an arc of an average radius of screen swing. A

It will be noted (Fig. 5) that the screen inclines upwardly immediately in front of the squeegee so that the pigment is not only forced through the screen but is permitted to coalesce over the underface of the screen before contact with the plate P so that the pigment is applied es an even coating on the plate. It will also be noted that the screen is also stripped vertically away from the plate and applied pigment immediately to the rear of the squeegee-thus insuring clear pigment boundaries on the plate.

By the time the squeegee has progressed across the patterned fabric the fabric has been lifted entirely free from the plate by the springs 3l. As the fabric is lifted from the plate the pigment clings both to the plate and to the fabric and consequently the fabric must be lifted from the plate considerably more than the thickness of deposited pigment before the viscosity of the pigment permits the fabric to be separated from the pigment.

Therefore, if the screen frame were fixed vertically during the pigmentapplication, and inherent flexibility of the fabric depended upon to cause withdrawal of the fabric immediately following pigment application to the plate, the fabric would have to be initially spaced a relatively considerable distance above the plate and would have to be so severely stretched during each pigment application that it would soon acquire a permanent sag which would render it unfit for further use.

In my device, however, the lowest position of the fabric, with frame S fully depressed, may be actually in contact with plate P yet, as the squeegee progresses toward the operator the passed-over portions of the fabric are promptly raised free from the pigment adhering to the plate and it fis never necessary to substantially stress vthe fabric so as to stretch it. Each pigment design is allowed to dry before the application of another pigment and by using appropriate pigmentsany desired combination and pattern of different colors may be successively applied to plates P, each color being accurately placed relative to, but not overlapping, adjacent colors, so that a single firing will serve to x the color pattern upon the plate without blurring.

By providing the multiplicity of pole-receiving perforations in the table, and the multiplicity of magnetic poles, said poles may be readily selectively positioned, in accordance with any particular color design, so that adequate anchoring and straightening of plates P may be attained without requiring contact of any pole. with any colorreceiving portion of the plates. As a consequence the plates may be reversed, for application of pigments to both faces without delay for intermediate drying.

I claim as my invention:

1. In combination, a table. a laterally distortable stenciling screen, means on said table and cooperable with said screen to guide one edge of said screen in a path substantially perpendicular to the surface of said table, means normally resiliently biasing said edge of said screen progressively away from the p`ane of said table, and means supporting the other end of the screen spaced from the table a distance slightly greater than the thickness of material to be stenciled but within the vertical distortion range of the patterned portion of the stencil.

, 2. vIn combination, a table, a stenciling screen, a pair of brackets independently slidably mounted on said table for adjustment laterally across the surface of said table, and means carried by each of said brackets and cooperable with an edge of said screen to lift said screen edge normally resiliently away from the plane of said table.

3. In combination, a table, a stenciling screen, a pair of relatively movable brackets mounted on said table, each of said brackets being formed with a slot extending substantially perpendicular to the surface of said table, pins carried by opposite sides of said screen adjacent one end thereof and receivable in said slots, and spring means carried by each of said brackets and cooperable with said screen to bias said one end thereof normally away from the plane of 4. In combination, a table, a stenciling screen, a pair of brackets adjustably mounted on said table, each of said brackets being formed with a slot extending substantially perpendicular to the surface of said table, and open at the free end of its bracket, pins carried by opposite sides of said screen adjacent Vone end thereof and receivable in'said slots, an upstanding post carried by each of said brackets, stop means adjustably and removably carried by one of said posts and adapted to be positioned in the path of movement of one of said pins, and springs connecting each of said pins with one of said posts and normally resiliently supporting said one screen end out of contact with said table surface.

5. The method of applying pigment in a pattern to a receiving surface, which comprises arranging a screen stencil over said surface, supplying pigment to said stencil, progressively forcing the pigment through the stencil beginning at one edge thereof and progressing toward the opposite edge, and simultaneously and progressively tilting the stencil as a whole to raise its beginning edge progressively from the surface ot' application, wherebyportions of the stencil through which pigment has been forced are progressively and increasingly raised from the application surface during progressive stencil penetration by the pigment.

6. The method of applying pigment in a pattern to a receiving surface which comprises arranging a laterally distortable screen stencil over said surface and spaced therefrom a dis.- tance not greater than the distortion range, supplying pigment to said stencil, forcing said pigment through the stencil beginning at one edge of the stencil and progressing in a narrow zone toward the opposite edge of the stencil, and

' simultaneously and progressively tilting the stensaid screen spaced from said article within theA flexibility-range of said screen, and vertically- A yielding means normally supporting the opposite edge of said screen in substantially greater spaced relation to said article and capable of progressively tilting the screen as a whole, whereby vertical pressure applied to said screen` upon lines substantially paralleling said two edges may produce line contact of screen with article and the yielding-supported edgel of the screen will be progressively and increasingly raised as said pressure line approaches the first-mentioned screen edge.

- CHARLES A. WULF. 

